ES2940094T3 - Rotary encoder with adaptable installation - Google Patents

Abstract

Rotary encoders are described. According to a first aspect, a rotary encoder comprises a rotor and a stator. The rotor and the stator are arranged in the rotary encoder in such a way that, when the rotary encoder is arranged in a machine comprising a shaft having an axis of rotation, a rotation of the rotor relative to the stator about the axis is allowed. of rotation of the shaft, a relative movement between the rotor and the stator along the axis of rotation of the shaft is restricted to a predetermined distance, and a movement of the rotor relative to the shaft along the axis of rotation of the shaft is allowed. axis. According to a second aspect, a movement of the stator with respect to the machine along the axis of rotation of the shaft is allowed. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Rotary encoder with adaptable installation

TECHNICAL FIELD

The present disclosure relates to rotary encoders.

BACKGROUND

Rotary encoders are used in industry for position and speed monitoring and are typically mounted as a rotating part, such as a motor or gearbox shaft. Mechanical stress, for example due to vibrations, is a reason for the malfunction of rotary encoders, thus generating unplanned shutdowns during operational use.

Exemplary rotary encoders are disclosed by EP 2338630 A1, US 4386270 A, EP 2136456 A1, EP 3330 676 A1 and EP 3392538 A1.

The size of rotary encoders is a limiting factor in many applications and therefore for such applications end users strive to have as small rotary encoder dimensions as possible. For this purpose, so-called bearing-free encoders are used in industry to monitor position and purpose. Small installation dimensions and high environmental specifications are advantageous properties of bearing free codings. Additionally, bearing-related failures are common failures within regular encoders, which is another reason bearing-free encoders are beneficial.

A problem may arise for prior art bearing-free encoders due to movement along an axis of rotation, on which the encoder is arranged. Such movements along the axis of rotation of the shaft can result, for example, from elongation of the shaft due to heat and can impact a relative position between a rotor and a stator in a bearingless encoder to such an extent that reduces the accuracy of bearing free encoder signals.

SUMMARY

An object of the present disclosure is to provide a rotary encoder that is intended to mitigate, alleviate, or eliminate one or more of the previously identified deficiencies in the art.

The present disclosure relates to a rotary encoder according to a first aspect. The rotary encoder according to the first aspect is described in claim 1.

By arranging the rotor in the rotary encoder in such a way that it is allowed to move relative to the shaft along an axis of shaft rotation, a movement of the shaft along the axis of rotation will not necessarily result in the same movement as would result for an arrangement, in which the rotor is fixed on the shaft and is not allowed to move relative to the shaft along the axis of rotation. Furthermore, by arranging the rotor and stator in the rotary encoder in such a way that the relative movement of the shaft is restricted to a predetermined distance, the rotor can be allowed freedom of movement along the axis of rotation of the shaft, without the relative distance between the stator and the rotor along the axis of rotation of the shaft varies more than is allowed for exact operation of the rotary encoder. In this way, the restriction of the distance of the relative movement between the rotor and the stator within the allowed limits for exact operation is achieved also for cases where a movement of the shaft along the axis of rotation is greater than the allowed limits. for exact performance.

The predetermined distance is generally selected such that the variation of the relative distance between the stator and the rotor along the axis of rotation of the shaft is less than or equal to a maximum variation that is allowed for exact operation of the rotary encoder in planned applications. The allowable variation may depend, for example, on whether the rotary encoder uses radial sensing or axial sensing and on the sensing/sensing technology used, such as capacitive, optical, inductive and magnetic sensing.

In rotary encoders, the detection by a stator of rotation of a rotor is performed in an axial direction, that is, along a direction of the axis of rotation of a shaft on which the rotor is arranged. This is different from radial sensing rotary encoders where sensing by a rotating stator of a rotor is in a radial direction of a rotary axis of a shaft on which the rotor is disposed.

The rotary encoder according to the first aspect further comprises a rotor supporting means and a stator supporting means. The rotor is attached to the rotor support means and the stator is attached to the support means. stator support. The rotor support means and the stator support means are furthermore arranged such that when the rotor support means is arranged on the shaft and the stator support means is arranged on the machine comprising the shaft , a rotation of the rotor support means relative to the stator support means is allowed about the axis of rotation of the shaft, and a relative movement between the rotor support means and the stator support means is restricted along from the axis of rotation of the shaft to the predetermined distance. The rotor support means is further arranged in such a way that, when it is arranged on the shaft, a movement of the rotor support means relative to the shaft along the axis of rotation of the shaft is allowed.

In other embodiments of the rotary encoder according to the first aspect, the stator support means comprises a first surface and a second surface and the rotor support means comprises a third surface and a fourth surface, wherein, when the rotary encoder means rotor support is provided on the shaft and the stator support means is provided on the machine comprising the shaft, the first surface facing the third surface in a direction along the axis of rotation of the shaft and the second surface facing toward the fourth surface in a direction along the axis of rotation of the shaft. The absolute value of the difference between a distance in one direction along the axis of rotation of the shaft from the first surface to the second surface and a distance in one direction along the axis of rotation of the shaft from the third surface to the fourth surface is the default distance.

By arranging the stator support means and the rotor support means such that there is a difference between the distances between the first surface and the second surface and the distance between the third surface and the fourth surface, the movement of the support means The rotor can only move along the axis of rotation of the shaft as long as this distance difference exists. More specifically, the movement along the axis of rotation of the rotor support means relative to the stator support means is limited in a direction along the axis of rotation by the first surface of the stator support means entering in contact with the third surface of the rotor support means. Movement along the axis of rotation of the rotor support means relative to the stator support means is limited in the other direction along the axis of rotation by the second contacting surface of the stator support means. with the fourth surface of the rotor support means.

In certain embodiments of the rotary encoder according to the first aspect, the distance in one direction along the axis of rotation of the shaft from the first surface to the second surface is greater than a distance in one direction along the axis of rotation of the tree from the third surface to the fourth surface.

The first surface, the second surface, the third surface and the fourth surface are preferably arranged such that, when the rotor support means is arranged on the shaft and the stator support means is arranged on the machine comprising the tree, the first surface, the second surface, the third surface and the fourth surface are disposed adjacent to the tree.

The closer the first surface and the second surface are to the axis of rotation, the slower the relative velocity between the first surface and the third surface will be at a specified number of rotations per unit time. This is beneficial in that the first surface and the third surface can come into contact when the shaft moves along the axis of rotation, for example due to thermal expansion. Reducing the relative speed due to the rotation between the first surface and the third surface will reduce the twisting forces that result from the first surface and the third surface coming into contact when the rotor support means is rotating. The same applies to the second surface and the fourth surface, which can come into contact when the shaft moves along the axis of rotation in the opposite direction.

In certain embodiments of the rotary encoder according to the first aspect, the rotor support means comprises first coupling means for coupling with corresponding second coupling means of the shaft, such that when the rotor support means is arranged on the shaft, a rotation of the rotor support means relative to the shaft about the axis of rotation of the shaft is prevented, and a movement of the rotor support means relative to the shaft along the axis of rotation of the shaft is allowed. tree.

The first coupling means may be spring-loaded protrusions arranged to engage second coupling means in the form of recesses in the shaft, which extend along the outer surface of the shaft in the direction of the axis of rotation of the shaft.

The present disclosure further relates to a rotary encoder according to a second aspect. The rotary encoder according to the second aspect is described in claim 7.

By arranging the stator in the rotary encoder in such a way that it is allowed to move relative to the machine along the axis of rotation of the shaft, any movement of the shaft along the axis of rotation in relation to the machine will not necessarily result in the same amount of relative movement between the shaft and the stator. Furthermore, by arranging the rotor and stator in the rotary encoder in such a way that the relative movement between the rotor and the stator along the axis of rotation of the shaft is restricted to a predetermined distance, the stator can be allowed freedom of movement. relative to the machine along the axis of rotation of the shaft without the relative distance between stator and rotor along the axis of rotation of the shaft varying more than is permitted for accurate operation of the rotary encoder. The restriction of the distance of the relative movement between the rotor and the stator within the limits allowed for exact operation is achieved also for cases where a movement of the shaft along the axis of rotation is greater than the limits allowed for exact operation. .

The predetermined distance is generally selected such that the variation of the relative distance between the stator and the rotor along the axis of rotation of the shaft is less than or equal to a maximum variation that is allowed for exact operation of the rotary encoder in planned applications. The allowable variation may depend, for example, on whether the rotary encoder uses radial sensing or axial sensing and on the technology used for sensing/sensing, such as capacitive, optical, inductive and magnetic sensing.

The rotary encoder according to the second aspect further comprises a rotor supporting means and a stator supporting means. The rotor is attached to the rotor support means and the stator is attached to the stator support means. The rotor support means and the stator support means are furthermore arranged such that when the rotor support means is arranged on a shaft, having an axis of rotation, and the stator support means is arranged on the machine comprising the shaft, a rotation of the rotor support means relative to the stator support means about the axis of rotation of the shaft is allowed, and a relative movement between the stator support means and the shaft is restricted. rotor support means along the axis of rotation of the shaft up to the predetermined distance. The stator support means is further arranged in such a way that, when it is arranged on the machine comprising the shaft, a movement of the stator support means relative to the shaft along the axis of rotation of the shaft is allowed. .

In certain embodiments of the rotary encoder according to the second aspect, the stator support means comprises a first surface and a second surface and the rotor support means comprises a third surface and a fourth surface. When the rotor support means is provided on the shaft and the stator support means is provided on the machine comprising the shaft, the first surface faces the third surface in a direction along the axis of rotation of the shaft and the second surface faces the fourth surface in a direction along the axis of rotation of the shaft. In addition, the absolute value of the difference between a distance in one direction along the axis of rotation of the shaft from the first surface to the second surface and a distance in one direction along the axis of rotation of the shaft from the third surface to the fourth surface is the default distance.

By arranging the stator support means and the rotor support means such that there is a difference between the distance between the first surface and the second surface and the distance between the third surface and the fourth surface, the movement of the support means The rotor can only move along the axis of rotation of the shaft, as long as this distance difference exists. More specifically, the movement along the axis of rotation of the rotor support means relative to the stator support means is limited in a direction along the axis of rotation by the first surface of the stator support means entering in contact with the third surface of the rotor support means. Movement along the axis of rotation of the rotor support means relative to the stator support means is limited in the other direction along the axis of rotation by the second contacting surface of the stator support means. with the fourth surface of the rotor support means.

In other embodiments of the rotary encoder according to the second aspect, the distance in one direction along the axis of rotation of the shaft from the first surface to the second surface is greater than a distance in one direction along the axis of rotation of the tree from the third surface to the fourth surface.

In the rotary encoder according to the second aspect, the stator support means comprises first coupling means for coupling with corresponding second coupling means of the machine. In certain embodiments, the first coupling means and the second coupling means are arranged in such a way that a rotation of the stator support means in relation to the machine about the axis of rotation of the shaft is prevented, and a movement is allowed. of the stator support means relative to the machine along the axis of rotation of the shaft, when the stator support means is arranged on the machine.

The first coupling means are arranged by means of bores to engage with corresponding second coupling means in the form of guide shafts arranged on the machine and extending in the direction of the axis of rotation of the shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particular description of the exemplary embodiments, as illustrated in the accompanying drawings, in which the same reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis is instead placed on illustrating exemplary embodiments.

Figure 1a illustrates a cross-sectional view of an embodiment of a rotary encoder according to the first aspect, when arranged on a machine including a shaft.

Figure 1b illustrates an exploded perspective cross-sectional view of the embodiment of the rotary encoder according to the first aspect.

Figures 2a-2d illustrate cross-sectional views of alternative implementations of a portion of embodiments of the rotary encoder according to the first aspect.

Figure 3a illustrates a cross-sectional view of an embodiment of a rotary encoder according to the second aspect.

Figure 3b illustrates a perspective cross-sectional view of the embodiment of a rotary encoder according to the second aspect.

Figure 4a illustrates a cross-sectional view of another embodiment of a rotary encoder according to the first aspect, when it is arranged on a machine including a shaft.

Figure 4b illustrates an exploded perspective cross-sectional view of the other embodiment of the rotary encoder according to the first aspect.

DETAILED DESCRIPTION

Aspects of the present disclosure will be described more fully below with reference to the accompanying drawings. However, the rotary encoder described here can be implemented in different ways and should not be construed as limited to the aspects presented here. The same numbers in the drawings refer to the same elements throughout the document.

The terminology used herein is for the purpose of describing particular aspects of the disclosure only, and is not intended to limit the invention. When used here, the singular forms "a", "a" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Figure 1a illustrates a cross-sectional view of one embodiment of a rotary encoder 10 according to the first aspect, when arranged on a machine 20 including a machine shaft 30. The encoder includes a rotor 12 and a stator 14. The rotor 12 is arranged on a rotor support means in the form of a bushing 15 and the stator 14 is arranged on a stator support means in the form of a casing 16. The rotation of the rotor 12 with respect to the stator it can be detected using any technology capable of detecting such changes. Examples of such technologies include capacitive, optical, inductive, and magnetic sensing. The rotary encoder may be configured as an absolute and/or incremental rotary encoder. The terms rotor and stator can refer to singular components as well as aggregates that serve a common rotor or stator function.

It should be noted that although the rotor 12 is shown arranged on the bushing 15 and the stator 14 is shown arranged on the casing 16 in Figure 1a, alternative arrangements would also be feasible in the embodiment illustrated in Figure 1a, where the rotor 12 is arranged by means of one or more additional means in the bushing 15 or the stator 14 is arranged by means of one or more additional means in the housing 16, in such a way that the rotor 12 is fixed in rotational and axial direction in the bushing 15 and the stator 14 is fixed in the rotational and axial direction in the casing 16.

The bushing 15 is arranged inside the housing 16. Furthermore, the bushing 15 is arranged on a stub shaft 32 which, in turn, is arranged on the shaft 30 of the machine 20. The stub shaft 32 is arranged on the machine shaft 30 through suitable fixing means (not shown), such that they have a common axis of rotation R such that relative movement along the axis of rotation R and relative rotation around it are prevented. of the axis of rotation between stub shaft 32 and machine shaft 30. Stub shaft 32 is generally used to provide a suitably adapted shaft for arranging bushing 15 on stub shaft 32, for example to provide suitable dimensions and coupling means. Alternatively, for a situation where shaft 30 of machine 20 is already easily adapted for bushing 15 arrangement, stub shaft 32 and rotary encoder 10 would not be required. it would be arranged directly on the shaft 30 of the machine 20.

The casing 16 is arranged on the machine 20 through fixing means 25a and 25b, in such a way that rotation of the casing 16 relative to the machine about the axis of rotation R is prevented.

The bushing 15 comprises first coupling means 17a and 17b in the form of spring-loaded protrusions. The stub shaft 32 comprises corresponding coupling means 34a and 34b in the form of recesses which extend along the outer surface of the stub shaft 32 in a direction of the axis of rotation R. The bushing 15 is then arranged on the stub shaft 32, in such a way that the first coupling means 17a and 17b engage with the second coupling means 34a and 34b, respectively, in such a way that a movement of the bushing 15 relative to the stub shaft 32 a is allowed. along the axis of rotation R, while rotation of the socket 15 relative to the stub shaft 32 about the axis of rotation R is prevented. For example, the protrusions may be spherical at least in the portion arranged to engage the recesses. and the recesses may have a V-shaped cross section along the axis of rotation R.

The housing 16 has a first surface 18a perpendicular to the axis of rotation R and a second surface 18b perpendicular to the axis of rotation R. The bushing 15 has a third surface 19a perpendicular to the axis of rotation R and a fourth surface 19b perpendicular to the axis of rotation A. The first surface 18a of the housing 16 faces the third surface 19a of the bushing 15, and the second surface 18b of the housing 16 faces the fourth surface 19b of the bushing 15. Furthermore, the housing 16 and the bushing 15 are arranged such that the distance from the first surface 18a to the second surface 18b is greater than the distance from the third surface 19a to the fourth surface 19b. Therefore, the casing 15 can be moved along the axis of rotation R from the first position relative to the casing 16, where the first surface 18a and the third surface 19a are in contact with a second position relative to the housing 16, where the second surface 18b is in contact with the fourth surface 19b. The difference between the distance from the first surface 18a to the second surface 18b and the distance from the third surface 19a to the fourth surface 19b, that is, from the first position to the second position, is selected for a predetermined distance. This will, in turn, restrict the relative movement of rotor 12 disposed on bushing 15 and stator 14 disposed on casing 16 within the predetermined distance. The predetermined distance is selected to be less than or equal to a maximum variation of the relative distance between rotor 12 and stator 14 allowed to produce signals of an accuracy required for an intended application of rotary encoder 10.

For example, the rotor 12 can be arranged on the bushing 15, the stator 14 can be arranged on the casing 16 and the bushing 15 can be arranged on the casing, in such a way that when the bushing 15 is in the first position, the distance between rotor 12 and stator 14 is a calibrated distance minus half the predetermined distance and when bushing 15 is in the second position, the distance between rotor 12 and stator 14 is the calibrated distance plus half the default distance. The calibrated distance is a distance identified as a suitable distance for operation, which can vary half the predetermined distance up and down, that is, allowing a variation of the predetermined distance, while still producing signals of an accuracy required for a intended application of rotary encoder 10. The calibrated distance is the distance between rotor 12 and stator 14, when bushing 15 is halfway between the first position and the second position.

Although the first surface 18a, the second surface 18b, the third surface 19a and the fourth surface 19b are all perpendicular to the axis of rotation R in the rotary encoder illustrated in Figure 1a, it should be noted that the surfaces may also have other individual angles in relative to the axis of rotation R and other individual shapes, provided that the surfaces interact in such a way as to restrict the relative movement between the bushing 15 and the housing 16, when the bushing 15 moves along the axis of rotation R from a position, up to a predetermined distance, where at least a portion of the first surface 18a and a portion of the third surface 19a are in contact, to a position, where at least a portion of the second surface 18b and a portion of the fourth surface 19b are in contact.

The rotary encoder 10 is arranged in such a way that the bushing 15 is slidably arranged on the stub shaft 32. When the stub shaft 32 moves in the axial direction, for example due to thermal expansion of the machine shaft 30, on which the stub shaft 32 is arranged, the bushing 15 can first move in the axial direction relative to the housing 16 together with the stub shaft 32. However, when the third surface 19a of the bushing 15 comes into contact with the first surface 18a of the housing 16, further axial movement of the bushing 15 towards the first surface 18a relative to the housing 16 is stopped. If the movement of the stub shaft 32 continues in the same direction, the bushing 15 is pushed to along the axis of rotation relative to stub shaft 32 by means of contact between the third surface 19a and the first surface 18a and the bushing 15 which is slidably arranged on the stub shaft 32. In a similar manner, the rotary encoder 10 is arranged in such a way that, when the fourth surface 19b of bushing 15 contacts the second surface 18b of housing 16 after axial movement of bushing 15, further axial movement of bushing 15 towards the first is stopped. surface 18b in relation to the housing 16. If the movement of the stub shaft 32 continues in the same direction, the bushing 15 is pushed along the axis of rotation relative to the stub shaft 32 by means of contact between the fourth surface 19b and the second surface 18b and bushing 15 is slidably arranged on stub shaft 32.

The rotor 12 should be arranged in the casing 16, in such a way as to allow rotation of the rotor 12 relative to the stator 14 around the axis of rotation R. For example, in figure 1a, the rotor 12 is arranged in a cavity 50 of the casing 16, in such a way that the rotation of the rotor 12 around the axis of rotation R is allowed.

It should be noted that the specific embodiment shown in Figure 1a is an example. Other embodiments of rotary encoders are possible according to the first aspect. For example, the shown embodiment identifies specific arrangements of a stator and a rotor in relation to a housing, a bushing, and a shaft. Alternative embodiments that meet the limitations of the independent claims on the relative movements and rotations of the stator, rotor, and shaft are possible. For example, the rotor and the stator may be arranged other than directly on the bushing and the casing, respectively. For example, they can be arranged on other parts which, in turn, are arranged on the bushing and the casing, respectively. Furthermore, the first surface, the second surface, the third surface and the fourth surface may be arranged other than on the bushing and the casing, respectively. For example, they can be arranged on other parts which, in turn, are arranged on the bushing and the casing, respectively. Generally, the first surface and the second surface should be arranged such that they are fixed relative to the stator in the axial direction and the third surface and the fourth surface should be arranged such that they are fixed relative to the rotor in the axial direction.

For example, there are alternatives to the embodiment illustrated in Figure 1a. In one such alternative, a stub shaft is arranged on the machine shaft in such a way that a relative movement along the axis R is allowed between the stub shaft and the machine shaft and where a means of Rotor support are arranged on the stub shaft in such a way that relative movement along the axis of rotation R between the rotor support means and the stub shaft is prevented.

In the rotary encoder 10 of Figure 1a, the rotor 12 and the stator 14 are arranged in such a way that the stator 14 is arranged at an equal radial distance from the axis of rotation R as at least a portion of the rotor 12. This differs of a radial sensing rotary encoder, where a stator would be arranged at a greater or lesser, but not equal, radial distance from an axis of rotation than a rotor.

Figure 1b illustrates an exploded perspective view of the embodiment of the rotary encoder 10 according to the first aspect. The stator 14 is adapted to be arranged in the upper part of the casing 16. Both the stator 14 and the upper part of the casing 16 have a bore in the center through which the stub shaft 32 can project when the encoder is turned on. The rotary 10 is disposed on the machine (not shown), including the shaft (not shown) on which the stub shaft 32 is disposed. The upper portion of the housing 16 includes the first surface 28a.

The rotor 12 is arranged on the bushing 15 and the bushing 15 has a bore for arranging the bushing 15 on the stub shaft 32. The first coupling means 17a and 17b in the form of two spring-loaded protrusions are arranged in such a way that the spring-loaded protrusions project into the bore of the bushing 15, in such a way that they engage with the second coupling means 34a and 34b in the form of two corresponding recesses in the stub shaft 32 when the bushing 15 is arranged on the stub shaft 32. The second coupling means 34a and 34b in the form of the two recesses extends along the axis of rotation R of the stub shaft 32, in such a way that when the bushing 15 is arranged on the shaft 32, the bushing 15 is allowed to move relative to the stub 32 along the axis of rotation R of the stub 32, but the bushing 15 is prevented from rotating relative to the stub 32 about the axis of rotation R of the stub shaft 32.

Furthermore, in figure 1b, the first surface 18a and the second surface 18b of the housing 16 are arranged in relation to the third surface 19a and the fourth surface 19b of the bushing 15, in such a way that the distance from the first surface 18a to the second surface 18b is greater than the distance from the third surface 19a to the fourth surface 19b. Therefore, the bushing 15 can be moved along the axis of rotation R from a first position relative to the housing 16, where the first surface 18a and the third surface 19a are in contact, to a second position relative to the casing 16, where the second surface 18b is in contact with the fourth surface 19b. The difference between the distance from the first surface 18a to the second surface 18b and the distance from the third surface 19a to the fourth surface 19b, that is, from the first position to the second position, is selected for a predetermined distance. This will, in turn, restrict the relative movement of the rotor 12 disposed on the casing 15 and the stator 14 disposed on the casing 16 within the predetermined distance. The predetermined distance is selected to be less than or equal to a maximum variation of the relative distance between rotor 12 and stator 14 allowed to produce signals of an accuracy required for an intended application of rotary encoder 10.

Figures 2a-2d illustrate cross-sectional views of alternative implementations of a portion of embodiments of the rotary encoder according to the first aspect. More specifically, Figures 2a-2d illustrate alternative arrangements of the first surface 18a; 118a; 218a; 318a and from the second surface 18b; 118b; 218b; 318b of casing 16; 116; 216; 316 and of the third surface 19a; 119a; 219a; 319a and of the fourth surface 19b; 119b; 219b; 319b of bushing 15; 115; 215; 315 in Figures 1a and 1b, to restrict the movement of the rotor (not shown) disposed on the bushing 15; 115; 215; 315 in relation to the stator (not shown) arranged on the casing 16; 116; 216; 316 restricted to a predetermined distance. The predetermined distance is selected to be less than or equal to a maximum variation of the relative distance between the rotor (not shown) and the stator (not shown) allowed to produce signals of a required accuracy for an intended application.

It should be noted that the distances between the surfaces have been adapted in Figures 2a-2d for illustration purposes and are not necessarily a true reflection of actual scales of a rotary encoder for real life application.

Fig. 2a illustrates a cross-sectional view of a portion of a rotary encoder according to the arrangement of the first surface 18a and the second surface 18b of the casing 16, and the third surface 19a and the fourth surface 19b of the bushing 15, as illustrated in figures 1a and 1b. The third surface 19a and the fourth surface 19b are arranged at the distal ends of the bushing 15 along the axis of rotation R. The housing 16 encloses the bushing in the axial direction R and the first surface 18a and the second surface 18b of the casing 16 are arranged opposite the third surface 19a and the fourth surface 19b, respectively. Furthermore, the first surface 18a, the second surface 18b, the third surface 19a, and the fourth surface 19b are all preferably arranged as close as possible to the axis of rotation R without interfering with the stub shaft 32 when the bushing 15 is disposed on stub shaft 32 by way of protrusion 17a which engages recess 34a. The closer the first surface 18a and the third surface 19a are to the axis of rotation, the smaller the relative distance between the first surface 18a and the third surface 19a will be at a specified number of rotations per unit time. This is beneficial because the first surface 18a and the third surface can come into contact when the stub shaft 32 moves along the axis of rotation R due to thermal expansion of the machine shaft (not shown), in which the stub shaft 32 is arranged. In a similar manner, the second surface 18b and the fourth surface 19b can come into contact when the stub shaft 32 moves along the axis of rotation R in the opposite direction.

The bushing 15 and the housing 16 are arranged in such a way that the difference between the distance from the first surface 18a to the second surface 18b and the distance from the third surface 19a to the fourth surface 19b are selected for a predetermined distance. This will, in turn, restrict the relative movement of the rotor (not shown) disposed on the bushing 15 and the stator (not shown) disposed on the casing (16) within the predetermined distance. The predetermined distance is selected to be less than or equal to a maximum variation of the relative distance between the rotor (not shown) and the stator (not shown) allowed to produce signals of a required accuracy for an intended application.

Figure 2b illustrates a sectional view of a portion of a rotary encoder according to a first alternative arrangement of the surfaces of a housing 116 and a bushing 115 to the arrangement illustrated in Figures 1a, 1b and 2a. The bushing 115 is provided with a projecting portion 160 and the third surface 119a and the fourth surface 119b are arranged on the distal surfaces of the projecting portion 160 along the axis of rotation R. The housing 116 is provided with a yoke 170 enclosing the projecting portion 160 of the bushing 115 along the axis of rotation R and the first surface 118a and the second surface 118b of the housing 116 are disposed on the two inner surfaces along the axis of rotation R opposite the third surface 119a and the fourth surface 119b, respectively.

The projecting portion 160 of the casing 115 and the fork 170 of the casing 116 are arranged such that the difference between the distance from the first surface 118a to the second surface 118b and the distance from the third surface 119a to the fourth surface 119b are selected for a predetermined distance. This will, in turn, restrict the relative movement of a rotor (not shown) disposed on bushing 115 and a stator (not shown) disposed on casing 16 within the predetermined distance. The predetermined distance is selected to be less than or equal to a maximum variation of the relative distance between the rotor (not shown) and the stator (not shown) allowed to produce signals of a required accuracy for an intended application.

Figure 2c illustrates a cross-sectional view of a portion of a rotary encoder according to a second alternative arrangement of surfaces of a housing 216 and a bushing 215 to the arrangement illustrated in Figures 1a, 1b and 2a. In this alternative, the housing 216 is provided with a projecting portion 260 and the first surface 218a and the second surface 218b are disposed on the distal surfaces of the projecting portion 260 along the axis of rotation R. The bushing 215 is provided with a yoke 270 enclosing the projecting portion 260 of the casing 216 along the axis of rotation R and the third surface 219a and the fourth surface 219b of the bushing 15 are disposed on the two inner surfaces along the axis of rotation R opposite the first surface 218a and the second surface 218b, respectively.

The projecting portion 260 of the housing 216 and the fork 270 of the bushing 215 are arranged such that the difference between the distance from the third surface 219a to the fourth surface 219b and the distance from the first surface 218a to the second surface 218b is selected for a predetermined distance. This will, in turn, restrict the relative movement of a rotor (not shown) disposed on bushing 215 and a stator (not shown) disposed on casing 16 within the predetermined distance. The predetermined distance is selected to be less than or equal to a maximum variation of the relative distance between the rotor (not shown) and the stator (not shown) allowed to produce signals of a required accuracy for an intended application.

Figure 2d illustrates a cross-sectional view of a portion of a rotary encoder according to a third alternative arrangement of surfaces of a housing 316 and a bushing 315 to the arrangement illustrated in Figures 1a, 1b and 2a. In this alternative, the bushing 315 is arranged to extend beyond the housing 316 at both distal ends along the axis of rotation R. The bushing is provided with a first projecting portion 360a and a second projecting portion 360b. The first surface 318a and the second surface 318b of the housing 316 are arranged on the two distal surfaces of the housing 316 along the axis of rotation R, respectively. The third surface 319a and the fourth surface 319b of the bushing 315 are disposed on the inner surface of the projecting portion 360b along the axis of rotation R, respectively, opposite the first surface 318a and the second surface 318b, respectively.

The projecting portion 360a of the bushing 15, the projecting portion 360b of the bushing 315, and the casing 316 are arranged such that the difference between the distance from the third surface 319a to the fourth surface 319b and the distance from the first surface 318a until the second surface 318b is selected for a predetermined distance. This will, in turn, restrict the relative movement of a rotor (not shown) disposed on bushing 315 and a stator (not shown) disposed on casing 316 within the predetermined distance. The predetermined distance is selected to be less than or equal to a maximum variation of the relative distance between the rotor (not shown) and the stator (not shown) allowed to produce signals of a required accuracy for an intended application.

Figure 3a illustrates a cross-sectional view and Figure 3b illustrates a perspective cross-sectional view of an embodiment of a rotary encoder 400 according to the second aspect for a machine arrangement (not shown) including a machine tree (not shown). The encoder includes a rotor 412 and a stator 414. The rotor 412 is provided on a rotor support means 432 and the stator 414 is provided on a stator support means in the form of a casing 416.

It should be noted that although rotor 412 is shown arranged on rotor support means 432 and stator 414 is shown arranged on casing 416 in Figures 3a and 3b, alternative arrangements would also be feasible in the embodiment illustrated in Figures 3a and 3b, where the rotor 412 is arranged by means of one or more additional means in the rotor support means 432 or the stator 414 is arranged by means of one or more additional means in the housing 416, in such a way that the rotor 412 is fixed in rotational and axial direction in rotor support means 432 and stator 414 is fixed in rotational and axial direction in casing 416.

The rotor support means 432 is arranged on the machine shaft (not shown) by means of suitable fixing means (not shown), in such a way that the rotor support means 432 and the machine shaft have a common axis of rotation R and in such a way as to prevent relative movement along the axis of rotation R and relative rotation about the axis of rotation R between the rotor support means 432 and the machine shaft 430.

The housing 416 is arranged on the machine (not shown) by means of first coupling means in the form of a first through-hole 422a and a second through-hole 422b and second coupling means in the form of a first guide shaft 425a and a second through-hole 425a. a second guide shaft 425b. The first through hole 422a and the second through hole 422b are arranged in the housing 416 of the rotary encoder 400, such that the housing 416 can be arranged over the first guide shaft 425a and a second guide shaft 425b through the first through hole 422a and the second through hole 422b, respectively. Furthermore, the first guide shaft 425a and a second guide shaft 425b are fixed on the machine through suitable fixing means (not shown). Such an arrangement will prevent rotation of the casing 416 relative to the machine about the axis of rotation R, but will allow movement of the casing 416 along the axis of rotation R relative to the machine.

The housing 416 has a first surface 418a perpendicular to the axis of rotation R and a second surface 418b perpendicular to the axis of rotation R. The rotor support means 432 has a third surface 419a perpendicular to the axis of rotation R and a fourth surface 419b perpendicular to the axis of rotation R. The first surface 418a of the casing 416 faces the third surface 419a of the rotor support means 432, and the second surface 418b of the casing 416 faces the fourth surface 419b of the rotor support means. rotor 432. Furthermore, the casing 416 and the rotor supporting means 432 are arranged such that the distance from the first surface 418a to the second surface 418b is greater than the distance from the third surface 419a to the fourth surface 419b. Therefore, the casing 416 can be moved along the axis of rotation R from a first position relative to the rotor support means 432, where the first surface 418a and the third surface 419a are in contact with a second position. in relation to the rotor support means 432, where the second surface 418b is in contact with the fourth surface 149b. The difference between the distance from the first surface 418a to the second surface 418b and the distance from the third surface 419a to the fourth surface 419b, that is, from the first position to the second position, is selected for a predetermined distance. This will, in turn, restrict the relative movement of rotor 412 disposed on rotor support means 432 and stator 414 disposed on casing 416 within the predetermined distance. The predetermined distance is selected to be less than or equal to a maximum variation of the relative distance between rotor 412 and stator 414 allowed to produce signals of an accuracy required for an intended application of rotary encoder 400.

For example, rotor 412 may be disposed on rotor support means 432, stator 414 may be disposed on casing 416, and rotor support means 432 may be disposed on casing 416 such that when the housing 416 is in the second position, the distance between rotor 412 and stator 414 is a calibrated distance minus half the predetermined distance, and when housing 416 is in the second position, the distance between rotor 412 and stator 414 is the calibrated distance plus half the default distance. The calibrated distance is a distance identified as a suitable distance for operation, which can vary half the predetermined distance up and down, that is, allowing a variation of the predetermined distance, while still producing signals of an accuracy required for a intended application of rotary encoder 400. The calibrated distance is the distance between rotor 412 and stator 414, when the rotor support means is halfway between the first position and the second position.

Although the first surface 418a, the second surface 418b, the third surface 419a and the fourth surface 419b are all perpendicular to the axis of rotation R in the rotary encoder illustrated in Figure 3a, it should be noted that the surfaces may also have other individual angles in relative to the axis of rotation R and other individual shapes, provided that the surfaces interact in such a way as to restrict the relative movement between the rotor support means 432 and the casing 416 to a predetermined distance, when the casing 416 is moved at along the axis of rotation R from a first position, where at least a portion of the first surface 418a and a portion of the third surface 419a are in contact, to a second position, where at least a portion of the second surface 418b and a portion of the fourth surface 419b are in contact.

The rotary encoder 400 is arranged such that the housing 416 is slidably arranged on the rotor support means 432 and on the machine (not shown). When the rotor support means 432 moves along the axis of rotation R, for example due to thermal expansion of the machine shaft (not shown), on which the rotor support means 432 is arranged, the means The rotor support means 432 can first be moved along the axis of rotation R relative to the casing 416. However, when the third surface 419a of the rotor support means 432 comes into contact with the first surface 418a of the casing 416, further relative movement along the axis of rotation R between rotor support means 432 and casing 416 is stopped by contact between third surface 419a and first surface 418a. If the movement of the rotor support means 432 continues in the same direction, the casing 416 is driven along the axis of rotation through contact between the third surface 419a and the first surface 418a and the casing 416 which is arranged slidably on the machine (not shown). In a similar manner, the rotary encoder 400 is arranged such that when the fourth surface 419b of the rotor support means 432 contacts the second surface 418b of the housing 416 after axial movement of the rotor support means rotor 432, further relative movement along the axis of rotation R between the rotor support means 432 and the casing 416 is stopped by contact between the fourth surface 419b and the second surface 418b. If the movement of the rotor support means 432 continues in the same direction, the casing 416 is driven along the axis of rotation R by means of contact between the fourth surface 419b and the second surface 418b and the casing 416 which is slidably arranged on the machine (not shown).

Rotor 412 should be arranged in casing 416 in such a way as to allow rotation of rotor 412 relative to stator 414 about the axis of rotation R. For example, in Figures 3a and 3b, rotor 412 is arranged in a cavity 450 of the casing 416, in such a way that the rotation of the rotor 412 in relation to the stator 414 about the axis of rotation R is allowed.

It should be noted that the specific embodiment shown in Figures 3a and 3b is an example. Other embodiments of rotary encoders are possible according to the second aspect. For example, the shown embodiment identifies specific arrangements of a stator and a rotor in relation to a housing and a stub shaft. Alternative arrangements are possible which meet the limitations of the independent claims on the relative movements and rotations of the rotor, stator and casing. For example, the rotor and the stator can be arranged other than directly on the stub shaft and on the housing, respectively. For example, they can be arranged on other parts which, in turn, are arranged on the stub shaft and on the housing, respectively. In addition, the first surface, the second surface, the third surface, and the fourth surface may be arranged other than on the bushing and the casing, respectively. For example, they can be arranged on other parts which, in turn, are arranged on the stub shaft and on the housing, respectively.

The embodiments illustrated in Figures 1a, 1b, 3a and 3b refer to rotary encoders 10; 400 axial detection. In axial sensing rotary encoders, sensing by a stator 14; 414 rotation of a rotor 12; 412 is made in an axial direction, that is, along a direction of an axis of rotation R of a shaft 32, on which the rotor 14 is arranged; 414.

Figure 4a illustrates a cross-sectional view of another embodiment of a rotary encoder 500 in accordance with the first aspect, when arranged on a machine 520 including a shaft 530. The rotary encoder 500 of Figure 4a differs from the rotary encoder 10 of Figures 1a and 1b because it is a radial detection encoder. In radial sensing rotary encoders, sensing by a rotating stator of a rotor is performed in a radial direction of an axis of rotation of a shaft, on which the rotor is arranged. The encoder 500 of Figure 4a includes a rotor 512 and a stator 514. The rotor 512 is disposed on a rotor support means in the form of a bushing 515 and the stator 514 is disposed on a stator support means in the form of a bushing 515. shaped like a casing 516. The rotation of the rotor 512 with respect to the stator can be detected using any technology capable of detecting such changes. Examples of such technologies include capacitive, optical, inductive, and magnetic sensing. The rotary encoder may be configured as an absolute and/or incremental rotary encoder. The terms rotor and stator can refer to individual components as well as aggregates, which serve a common rotor and stator function.

The bushing 515 is disposed within the housing 516. In addition, the bushing 515 is disposed on a stub shaft 532 which, in turn, is disposed on the shaft 530 of the machine 520. The stub shaft 532 is disposed on the machine shaft 530 through suitable fixing means (not shown), in such a way that they have a common axis of rotation R and in such a way that relative movement along the axis of rotation R and relative rotation are prevented about the axis of rotation R between the stub shaft 532 and the machine shaft 530.

The casing 516 is arranged on the machine 520 through fixing means 525a and 525b, in such a way that the rotation of the casing 516 relative to the machine about the axis of rotation R is prevented.

Bushing 515 comprises first engagement means 517a and 517b in the form of spring-loaded protrusions. The stub shaft 532 comprises corresponding coupling means 534a and 534b in the form of recesses which extend along the outer surface of the stub shaft 32 in a direction of the axis of rotation R. The bushing 515 is then arranged on the shaft 532, in such a way that the first coupling means 517a and 517b engage with the second coupling means 534a and 534b, respectively, in such a way as to allow movement of the bushing 515 relative to the stub shaft 532 along along the axis of rotation R, while rotation of the socket 515 relative to the stub shaft 532 about the axis of rotation R is prevented. For example, the protrusions may be spherical, at least in the portion arranged to engage the recesses. and the recesses may have a V-shaped cross section along the axis of rotation R.

Housing 516 has a first surface 518a perpendicular to the axis of rotation R and a second surface 518b perpendicular to the axis of rotation R. Bushing 515 has a third surface 519a perpendicular to the axis of rotation R and a fourth surface 519b perpendicular to the axis of rotation A. The first surface 518a of the housing 516 faces the third surface 519a of the bushing 515, and the second surface 518b of the housing 516 faces the fourth surface 519b of the bushing 515. In addition, the housing 516 and bushing 515 are arranged such that the distance from the first surface 518a to the second surface 518b is greater than the distance from the third surface 519a to the fourth surface 519b. Therefore, the bushing 515 can be moved along the axis of rotation R from a first position relative to the housing 516, where the first surface 518a and the third surface 519a are in contact, to a second position relative to the housing 516, where the second surface 518b is in contact with the fourth surface 519b. The difference between the distance from the first surface 518a to the second surface 518b and the distance from the third surface 519a to the fourth surface 519b, that is, from the first position to the second position, is selected for a predetermined distance. This will, in turn, restrict the relative movement of rotor 512 disposed on bushing 515 and stator 514 disposed on casing 16 within the predetermined distance. The predetermined distance is selected to be less than or equal to a maximum variation of the relative distance between rotor 512 and stator 514 allowed to produce signals of an accuracy required for an intended application of rotary encoder 510.

The rotor 512 is arranged in a cavity 550 of the casing 516, in such a way that the rotation of the rotor 512 relative to the stator 514 about the axis of rotation R is allowed.

Figure 4b illustrates an exploded perspective cross-sectional view of the other embodiment of the rotary encoder according to the first aspect and a tree.

Fig. 4b illustrates an exploded perspective cross-sectional view of the other embodiment of the rotary encoder 500 according to the first aspect. An upper part of the casing 516 has a hole in the center, through which the stub shaft 532 can project, when the rotary encoder 500 is arranged on the machine (not shown), which includes the shaft (not shown). , on which the stub shaft 532 is disposed. The upper portion of the housing 516 includes the first surface 518a.

The rotor 512 is arranged on the bushing 515 and the bushing 515 has a bore for arranging the bushing 515 on the stub shaft 532. The first coupling means 517a and 517b in the form of two spring-loaded protrusions are arranged in such a way that the spring-loaded protrusions project into the bore of the bushing 515, in such a way that they engage with the second coupling means 534a and 534b in the form of two corresponding recesses in the stub shaft 532, when the bushing 515 is arranged on stub shaft 532. The second coupling means 534a and 534b in the form of the two recesses extend along the axis of rotation R of stub shaft 532, in such a way that, when bushing 515 is arranged on stub 532, bushing 515 is allowed to move relative to stub 532 along the axis of rotation R of stub 532, but bushing 515 is prevented from rotating relative to stub 532 about the axis of rotation R of the stub shaft 532.

The stator 514 is disposed in the lower portion of the case 516. The lower portion of the case 516 further includes the second surface 518b.

Furthermore, in Figure 4b, the first surface 518a and the second surface 518b of the housing 516 are arranged in relation to the third surface 519a and the fourth surface 519b of the bushing 515, such that the distance from the first surface 518a to the second surface 518b is greater than the distance from the third surface 519a to the fourth surface 519b. Therefore, the bushing 515 can be moved along the axis of rotation R from a first position relative to the housing 516, where the first surface 518a and the third surface 19a are in contact, to a second position relative to the housing 516, where the second surface 518b is in contact with the fourth surface 519b. The difference between the distance from the first surface 518a to the second surface 518b and the distance from the third surface 519a to the fourth surface 519b, that is, from the first position to the second position, is selected for a predetermined distance. This will, in turn, restrict the relative movement of rotor 512 disposed on bushing 515 and stator 514 disposed on casing 516 within the predetermined distance. The predetermined distance is selected to be less than or equal to a maximum variation of the relative distance between rotor 512 and stator 514 allowed to produce signals of an accuracy required for an intended application of rotary encoder 500.

Alternative arrangements of the first surface 18a; 118a; 218a; 318a and from the second surface 18b; 118b; 218b; 318b of casing 16; 116; 216; 316, and the third surface 19a; 119a; 219a; 319a and the fourth surface 19b; 119b; 219b; 319b of bushing 15; 115; 215; 315 illustrated in Figures 2a-d are applicable also for the first surface 518a and the second surface 518b of the housing 516, and for the third surface 519a and the fourth surface 519b of the bushing 515 of the other embodiment illustrated in Figures 4a and 4b. The surfaces are arranged in such a way that the movement of the rotor 512 disposed on the bushing 515 relative to the stator 514 disposed on the casing 516 is restricted up to a predetermined distance. The predetermined distance is selected to be less than or equal to a maximum variation of the relative distance between rotor 512 and stator 514 allowed to produce signals of a required accuracy for an intended application.

Although some of the figures have been limited to illustrating only certain aspects of the disclosed rotary encoders, it should be understood that technical features disclosed in relation to a certain embodiment or aspect may apply to any other embodiment or aspect, unless otherwise stated. explicitly that such a combination is impossible. In other words, the features illustrated in relation to Figures 1 to 3 can be freely combined, unless otherwise stated.

The description of the exemplary embodiments provided herein has been presented for purposes of illustration. The description is not intended to be exhaustive or to limit the exemplary embodiments to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of various alternatives to the provided embodiments. The examples described herein were selected and described to explain the principles and nature of exemplary embodiments and their practical application to enable those skilled in the art to use the exemplary embodiments in various ways and with various modifications, where appropriate for the particular use contemplated. . The features of the embodiments described here can be combined in all possible combinations of apparatus, modules and systems. It should be appreciated that the exemplary embodiments presented herein may be practiced in any combination with one another. Furthermore, many variations and modifications can be made to these embodiments. However, the scope of protection is only defined by the appended claims.

It should be noted that the word "comprising" does not necessarily exclude the presence of other elements or steps than those listed and the words "one" or "an" preceding an element do not exclude the presence of a plurality of such elements. It should be noted that any reference signs do not limit the scope of the claims. Furthermore, although specific terms are used, they are used only in a generic and descriptive sense and not for purposes of limitation.

Claims (10)

A rotary encoder (10), comprising a rotor (12; 112; 212; 312) and rotor support means (15; 115; 215; 315) in the form of a bushing, and a stator (14; 114; 214; 314) and stator support means (16; 116; 216; 316), wherein the rotor (12; 112; 212; 312) is attached to the rotor support means (15; 115; 215; 315) and the stator (14; 114; 214; 314) is attached to the support means of the stator (16; 116; 216; 316), wherein the rotor (12; 112; 212; 312) and the stator (14; 114; 214; 314) are arranged on the rotary encoder (10), such that, when the rotary encoder (10) is arranged on a machine (20) comprising a shaft (30; 32) having an axis of rotation (R): a rotation of the rotor (12; 112; 212; 312) relative to the stator (14; 114; 214; 314) around the axis of rotation (R) of the shaft (30; 32) is allowed, a relative movement between the rotor (12; 112; 212; 312) and the stator (14; 114; 214; 314) along the axis of rotation (R) of the shaft (30; 32) is restricted up to a predetermined distance , and a movement of the rotor (12; 112; 212; 312) relative to the shaft (30; 32) along the axis of rotation (R) of the shaft (30; 32), the rotor support means (15 ; 115; 215; 315) and the stator support means (16; 116; 216; 316) are further arranged in such a way that, when the rotor support means (15; 115; 215; 315) are arranged on the shaft (30; 32 ) and the stator support means (16; 116; 216; 316) are arranged on the machine (20) comprising the shaft (30; 32), a rotation of the rotor support means (15; 115) is allowed ; 215; 315) relative to the stator support means (16; 116; 216; 316) about the axis of rotation (R) of the shaft (30; 32), and a relative movement between the support means is restricted of the rotor (15; 115; 215; 315) and the stator support means (16; 116; 216; 316), along the axis of rotation (R) of the shaft (30; 32) up to a predetermined distance, The rotor support means (15; 115; 215; 315) are further arranged in such a way that, when they are arranged on the shaft (30; 32), a movement of the rotor support means (15) is allowed. ; 115; 215; 315) relative to the shaft (30; 32), along the axis of rotation (R) of the shaft (30; 32). The rotary encoder (10) of claim 1, wherein the stator support means (16; 116; 216; 316) comprises a first surface (18a; 118a; 218a; 318a) and a second surface (18b; 118b; 218b; 318b), and the rotor support means (15; 115; 215; 315) comprise a third surface (19a; 119a; 219a; 319a) and a fourth surface (19b; 119b; 219b; 319b), wherein when the rotor support means (15; 115; 215; 315) are arranged on the shaft (30; 32), and the stator support means (16; 116; 216; 316) are arranged on the machine (20), comprising the tree: the first surface (18a; 118a; 218a; 318a) faces the third surface (19a; 119a; 219a; 319a) in a direction along the axis of rotation (R) of the shaft, the second surface (18b; 118b; 218b; 318b) looks towards the fourth surface (19b; 119b; 219b; 319b), in a direction along the axis of rotation (R) of the shaft (30; 32), the absolute value of the difference between a distance in one direction along the axis of rotation (R) of the shaft (30; 32) from the first surface (18a; 118a; 218a; 318a) to the second surface (18b; 118b ; 218b; 318b) and a distance in a direction along the axis of rotation (R) of the shaft (30; 32) from the third surface (19a; 119a; 219a; 319a) to the fourth surface (19b; 119b; 219b; 319b) is the default distance. The rotary encoder (10) of claim 2, wherein the distance in one direction along the axis of rotation (R) of the shaft (30; 32) from the first surface (18a; 118a; 218a; 318a) to the second surface (18b; 118b; 218b; 318b) is greater than a distance in one direction along the axis of rotation (R) of the shaft (30; 32) from the third surface (19a; 119a; 219a; 319a ) to the fourth surface (19b; 119b; 219b; 319b). The rotary encoder of any one of claims 2 and 3, wherein, when the rotor support means (15; 115; 215; 315) is arranged on the shaft (30; 32) and the rotor support means stator (16; 116; 216; 316) are arranged on the machine (20), which comprises the shaft (30; 32), the first surface (18a; 118a; 218a; 318a), the second surface (18b; 118b; 218b; 318b), the third surface (19a; 119a; 219a; 319a) and the fourth surface (19b; 119b; 219b; 319b) are arranged adjacent to the tree. The rotary encoder (10) of any one of claims 1 to 4, wherein the rotor support means (15; 115; 215; 315) comprise first coupling means (17a, 17b) for coupling with second means coupling (34a, 34b) corresponding to the shaft (30; 32), in such a way that, when the rotor support means (15; 115; 215; 315) are arranged on the shaft (30; 32): a rotation of the rotor support means (15; 115; 215; 315) in relation to the shaft (30; 32) about the axis of rotation (R) of the shaft (30; 32) is prevented and a movement of the rotor support means (15; 115; 215; 315) in relation to the shaft (30; 32) along the axis of rotation (R) of the shaft (30; 32) is allowed. The rotary encoder (10) of claim 5, wherein the first engagement means (17a, 17b) are spring-loaded protrusions arranged to engage the second engagement means (34a, 34b), wherein the second engagement means coupling (34a, 34b) are corresponding recesses of the shaft (30; 342), which extend along the outer surface of the shaft (30; 32) in the direction along the axis of rotation (R) of the shaft (30;32). 7. A rotary encoder (400), comprising a rotor (412) and rotor support means (432) and a stator (414) and stator support means (416), comprising first coupling means which are bores through bushings (422a, 422b) arranged to engage with corresponding second coupling means in the form of guide shafts (425a, 425b) arranged on a machine comprising a shaft having an axis of rotation (R), which guide shafts are extend in the direction of the axis of rotation (R), wherein the rotor (412) is attached to the rotor support means (432), and the stator (414) is attached to the stator support means (416), wherein the rotor (412) and the stator (414) are arranged in the rotary encoder (400), in such a way that, when the rotary encoder is arranged on the machine: a rotation of the rotor (412) in relation to the stator (414) around the axis of rotation (R) of the shaft is allowed, a relative movement between the rotor (412) and the stator (414) is restricted along the axis of rotation (R) of the shaft up to a predetermined distance, and a movement of the stator (412) relative to the machine is allowed along the axis of rotation (R) of the shaft, wherein the rotor support means (432) and the stator support means (416) are further arranged in such a way that when the rotor support means (432) are arranged on the shaft having the axis of rotation (R) and the stator support means (416) are arranged on the machine comprising the shaft, a rotation of the rotor support means (432) is allowed in relation to the stator support means (416 ) about the axis of rotation (R) of the shaft, and a relative movement is restricted between the stator support means (416) and the rotor support means (432) along the axis of rotation (R) of the shaft up to a predetermined distance, and the stator support means (416) are arranged in such a way that, when they are arranged on the machine that comprises the shaft, movement of the stator support means (416) along the axis of rotation (R) of the shaft is allowed. The rotary encoder (400) of claim 7, wherein the stator support means (416) comprises a first surface (418a) and a second surface (418b), and the rotor support means (432) comprises a third surface (419a) and a fourth surface (419b), wherein, when the rotor support means (432) are arranged on the shaft and the stator support means (416) are arranged on the machine comprising the tree: the first surface (418a) faces the third surface (419a) in a direction along the axis of rotation (R) of the shaft, the second surface (418a) faces the fourth surface (419b) in a direction along the axis of rotation (R) of the shaft, the absolute value of the difference between a distance in one direction along the axis of rotation (R) of the shaft from the first surface (418a) to the second surface (418b) and a distance in one direction along the axis of rotation (R) of the shaft from the third surface (419a) to the fourth surface (419b) is the predetermined distance. The rotary encoder (400) of claim 8, wherein the distance in one direction along the axis of rotation (R) of the shaft from the first surface (418a) to the second surface (418b) is greater than one distance in a direction along the axis of rotation (R) of the shaft from the third surface (419a) to the fourth surface (419b). The rotary encoder (400) of any one of claims 7 to 9, wherein the stator support means (416) comprises first coupling means (422a, 422b) for coupling with second coupling means (425a, 525b). ) corresponding arranged on the machine, in such a way that: a rotation of the stator support means (416) relative to the machine around the axis of rotation (R) of the shaft is prevented, and a movement of the stator support means (416) in relation to the machine along the axis of rotation (R) of the shaft is allowed.